Platelet antiaggregation therapy and subinguinal endovascular revascularization.

BACKGROUND: Platelet antiaggregation therapy (PAT) is widely acknowledged to be a positive prognostic factor after revascularization, either at the coronary or the peripheral level. This study evaluated the results of infrainguinal endovascular procedures performed for critical ischemia, in accordance with patient compliance to clopidogrel treatment. MATERIALS AND METHODS: This retrospective study included patients who underwent infrainguinal endovascular therapy for critical ischemia between January 2003 and December 2009. For 1 month, patients received the same postoperative PAT protocol: aspirin associated with clopidogrel, and then clopidogrel in the long term. Patient follow-up was set at 3 months, 6 months, 1 year, and then yearly thereafter. Survival rates, primary patency (PP), and limb salvage (LS) were studied in accordance with therapy compliance. Patients were classified into 2 groups: group 1 for compliant patients and group 2 for noncompliant patients in the long term. From January 2003 to December 2009, 153 infrainguinal endovascular procedures were performed on 150 patients experiencing critical ischemia who had benefited from the authors' postoperative PAT protocol. RESULTS: Both groups were comparable in terms of comorbidity. Of the procedures performed in groups 1 (N = 105) and 2 (N = 45), 62.8% (n = 66) and 44.4% (n = 20), respectively, were femoral, 14.3% (n = 15) and 22.2% (n = 10), respectively, were infrapopliteal, and 22.9% (n = 24) and 33.4% (n = 15), respectively, were mixed. Mean follow-up time was 30.3 ± 20.2 months (range, 1-70 months). The survival rate was comparable between the groups (P = 0.46). PP and LS rates were significantly higher in group 1 than in group 2 (PP: 84% vs. 80%, respectively, at 1 year, 79% vs. 50%, respectively, at 2 years, 65% vs. 30%, respectively, at 3 years, and 60% vs. 18%, respectively, at 4 years; P = 0.02; LS: 92% vs. 78%, respectively, at 1 year, 86% vs. 62%, respectively, at 2 years, 80% vs. 55%, respectively, at 3 years, and 77% vs. 36%, respectively, at 4 years; P = 0.04). CONCLUSIONS: This study shows that in common practice, 31% of patients stop their clopidogrel therapy, with a negative impact on PP and LS. These results indicate that medical follow-up after endovascular surgery must be reinforced.

Arterial thrombosis after using Angio-Seal.

Percutaneous closure systems of arterial puncture sites are being used more and more in modern endovascular practice. In this article, we report five cases of thrombotic complications following Angio-Seal deployment which required to be treated in our department between June 2004 and January 2006. We carried out a computerized literature review using "vascular closure" as a keyword and elected 106 articles published between 1992 and 2007. The analysis of this literature review showed that the rate of percutaneous closure complications was similar to the rate of manual compression complications, which is still the reference method. The complications associated with the use of these systems were more complex and more often required surgical repair. The severity and frequency of these complications differ based on the type of closure systems. The vascular surgeon in charge must have a good knowledge of these systems and of the complications each of them entails to be able to treat them in the most appropriate way.

Prehospital treatment of infrarenal ruptured abdominal aortic aneurysms: a multicentric analysis.

BACKGROUND: The aim of this study was to evaluate the quality of the current treatment of patients presenting with ruptured abdominal aortic aneurysms (RAAAs), from the first symptoms to the operating room with an analysis of preoperative mortality risk factors. METHODS: For 3 years, in four vascular surgery departments, we have collected all the consecutive cases of patients operated on for RAAA. We analyzed the initial clinical situation, the means of transportation, the time elapsed before treatment, and the mortality rate at 3 days. Sixty-six RAAAs were operated on. Mean patient age was 76 years (range, 52-93 years). RESULTS: The initial symptoms were a precisely located pain either abdominal (45.3%), lumbar (17.2%), or both (14.1%) or feeling faint (10.9%). In 22.7% of the cases, an initial hemodynamic instability was observed. In 46.8% of the cases, patients first went to a peripheral hospital before being admitted into a referral centre. In 84.5% of the cases, medical mean of transportation was used. The mean distance covered was 59.8 kilometers (range, <5 km to 213 km). The initial diagnosis was accurate in 67.3% of the cases. The mean intrahospital waiting period between the arrival at a reference center and the admission into an operating room was 127 minutes. Global mortality rate was 44.2%. The main preoperative mortality factor to be noticed was the initial hemodynamic instability (p=0.0031). Among stable patients, only two of them (5.4%) worsened during the preoperative treatment. CONCLUSION: In our study, hemodynamic instability corresponds to the main prognosis factor of mortality. In most cases, the initial stability persisted and allowed additional evaluation. However, the intrahospital waiting periods appeared to be too long. To be optimal, the adequate treatment should be specifically designed as soon as a diagnosis has been established.

Effect of chronic pre-treatment with angiotensin converting enzyme inhibition on skeletal muscle mitochondrial recovery after ischemia/reperfusion.

Impaired skeletal muscle energetic participates in peripheral arterial disease (PAD) patient's morbidity and mortality. Angiotensin converting enzyme inhibition (ACEi), cornerstone for pharmacologic risk factor management in PAD patients, might also be interesting by protecting skeletal muscle energetic. We therefore determined whether chronic ACEi might reduce ischemia-induced mitochondrial respiratory chain dysfunction in the frequent setting of hindlimb ischemia-reperfusion. Ischemic legs of rats submitted to 5 h ischemia induced by a rubber band tourniquet applied on the root of the hindlimb followed by reperfusion without (IR, n = 11) or after ACEi (n = 14; captopril 40 mg/kg per day during 28 days before surgery) were studied and compared to that of sham-operated animals (n = 11). The effect of ACEi on the non-ischemic contralateral leg was also determined in the ACEi group. Maximal oxidative capacities (V(max)) and complexes I, II and IV activities of the mitochondrial respiratory chain of the gastrocnemius muscle were determined using glutamate-malate, succinate and TMPD-ascorbate substrates. Arterial blood pressure was significantly decreased after ACEi (124 +/- 2.8 vs. 108 +/- 4.19 mmHg; P = 0.01). Ischemia-reperfusion reduced V(max) (4.4 +/- 0.4 vs. 8.7 +/- 0.5 micromol O2/min/g dry weight, -49%, P < 0.001), affecting mitochondrial complexes I, II and IV activities. ACEi failed to modulate ischemia-induced dysfunction (V(max) 5.1 +/- 0.7 micromol O2/min/g dry weight) or the non-ischemic contralateral muscle respiratory rate. Ischemia-reperfusion significantly impaired the mitochondrial respiratory chain I, II and IV complexes of skeletal muscle. Pharmacologic pre-treatment with ACEi did not prevent or increase such alterations. Further studies might be useful to improve the pharmacologic conditioning of PAD patients needing arterial revascularization.

Contralateral leg as a control during skeletal muscle ischemia-reperfusion.

BACKGROUND: Recent data demonstrated that hind limb ischemia induces skeletal muscle mitochondrial dysfunctions. Improvement of such metabolic myopathy improves patient's symptomatology, supporting the development of experimental models focused on mitochondrial function analysis. However, although the nonischemic contralateral leg is often used as a control during unilateral leg ischemia, whether it might be useful when assessing ischemia-induced mitochondrial dysfunction remains to be investigated. MATERIALS AND METHODS: Both ischemic (IR) and nonischemic contralateral legs (CTL) of rats (n=13) submitted to 5 h ischemia induced by a rubber band tourniquet applied on the root of the hind limb were studied and compared to that of sham-operated animals (SHAM, n=13). Maximal oxidative capacities (V(max)) and complexes I, II and IV activities of the gastrocnemius mitochondrial respiratory chain were determined, using glutamate-malate, succinate (Vs) and TMPD-ascorbate (V(TMPD)) substrates. RESULTS: V(max) was decreased in IR (4.6+/-0.4 microM/min/g dry weight) compared to both SHAM and CTL muscles (8.5+/-0.5 and 7.1+/-0.4 microM/min/g dry weight, -46% and -36%, P<0.001, respectively). V(S) and V(TMPD) were reduced in IR muscle (-56% and -48% for V(S); and -25% and -24% for V(TMPD), P<0.001) as compared to SHAM and CTL). V(S) and V(TMPD) were similar in SHAM and CTL muscles. CONCLUSIONS: Five hours ischemia-reperfusion significantly impaired complexes I, II and IV of the ischemic skeletal muscle mitochondrial respiratory chain. Interestingly, only V(max) was slightly altered in the contralateral leg, supporting that the nonischemic leg might be used as a control when assessing mitochondrial function in the experimental setting of unilateral hind limb ischemia.

In vitro approach to the dilative behavior of knitted vascular prosthetic grafts.

The purpose of this report is to propose an in vitro approach to predicting the long-term dilative behavior of knitted polyester prosthetic grafts. Various techniques were applied to five warp knitted fabric prosthetic grafts in order to determine the following fabric properties: knitted fabric structure, textile structure, number and respective linear density of threads and strands, and length of yarn in each stitch. Following these investigations, the prosthetic grafts underwent testing to determine specific strength at break, breaking extension, and stress-strain curve. On two prosthetic grafts, image analysis was performed during circumferential tensile strength testing in order to monitor changes in structural features as a function of stress. Changes in the distance between two wales and two courses of stitches and stitch surface were measured. In addition to surface deformation, thickness was measured, using an induction sensor. Study of fabric structure showed many differences between the five models made by different manufacturers. Knit fabric structure was Indeforma in three cases and half-tricot in two. Strand number and size varied greatly from one model to another. Pattern also varied from one model to another, with knit stitch density varying from 1 to 3. Specific strength at break testing showed great differences in the mechanical properties of the grafts. These differences were especially obvious in the first part of the rheograms, which reflects the ability of the graft to comply in response to low-strength forces, i.e., much lower than those necessary to cause rupture. Image analysis of stitch behavior under stress further confirmed differences in graft behavior depending on the fabric structure adopted by the manufacturers. The in vitro approach proposed in this study to analyze the fabric characteristics of knitted prosthetic grafts effectively revealed differences in construction and behavior. These differences could account for differences in the dilative behavior of grafts in vivo.

Characterization of polyelectrolyte multilayer films on polyethylene terephtalate vascular prostheses under mechanical stretching.

Layer-by-layer (LBL) polyelectrolyte films offer extensive potentials to enhance surface properties of vascular biomaterials. From the time of implantation, PET prostheses are continuously subjected to multiple mechanical stresses such as important distorsions and blood pressure. In this study, three LBL films, namely (1) poly(sodium 4-styrenesulfonate)/poly(allylamine hydrochloride), (2) poly(L-lysine)/hyaluronan, and (3) poly(L-lysine)/poly(L-glutamic acid) were built on to isolated PET filaments, thread, and vascular prostheses. The three LBL films uniformly covered the surface of the PET samples with rough, totally smooth, and "wrinkled" appearances respectively for (PAH/PSS)(24), (PLL/HA)(24), and (PLL/PGA)(24) systems. We then assessed the behavior of these LBL films, in an aqueous environment [by environmental scanning electronic microscopy (ESEM)], when subjected to unidirectional longitudinal stretches. We found that stretching induces ruptures in the multilayer films on isolated filaments for longitudinal stretches of 14% for (PSS/PAH)(24), 13% for (PLL/PGA)(24), and 30% for (PLL/HA)(24) films. On threads, the rupture limit is enhanced to be respectively 26, 20, and 28%. Most interestingly, we found that on vascular prosthesis no rupture is visible in any of the three multilayers types, even for elongations of 200% (200% undergone by the PET prostheses is representative of those encountered during graft deployment) which by far exceeds elongations observed under physiological conditions (10-20%, blood pressure). In term of mechanical behaviors, these preliminary data constitute a first step toward the possible use of LBL film to coat and functionalize vascular prosthesis.

Ischemic preconditioning specifically restores complexes I and II activities of the mitochondrial respiratory chain in ischemic skeletal muscle.

OBJECTIVE: Defective mitochondrial function has been reported in patients presenting with peripheral arterial disease, suggesting it might be an important underlying mechanism responsible for increased morbidity and mortality. We therefore determined the effects of prolonged ischemia on energetic skeletal muscle and investigated whether ischemic preconditioning might improve impaired electron transport chain and oxidative phosphorylation in ischemic skeletal muscle. METHODS: Thirty rats were divided in three groups: the control group (sham, n = 9) underwent 5 hours of general anesthesia without any ischemia, the ischemia-reperfusion (IR) group (n = 11) underwent 5 hours ischemia induced by a rubber band tourniquet applied on the left root of the hind limb, and in the third group, preconditioning (PC group, n = 10) was performed just before IR and consisted of three cycles of 10 minutes of ischemia, followed by 10 minutes reperfusion. Maximal oxidative capacities (V(max)) of the gastrocnemius muscle and complexes I, II, and IV of the mitochondrial respiratory chain were determined using glutamate-malate (V(max)), succinate (V(s)), and N, N, N,'N'-tetramethyl-p-phenylenediamine dihydrochloride ascorbate as substrates. RESULTS: Physiologic characteristics were similar in the three groups. Ischemia reduced V(max) by 43% (4.5 +/- 0.4 vs 7.9 +/- 0.5 micromol O(2)/(min x g dry weight), P < .01) and V(s) by 55% (2.9 +/- 0.3 vs 6.3 +/- 0.4 micromol O(2)/min/g dry weight; P < .01) in the IR and sham groups, respectively, and impairments of mitochondrial complexes I and II activities were evident. Of interest was that preconditioning prevented ischemia-induced mitochondrial dysfunction. Both V(max) and V(s) were significantly higher in the PC rats than in IR rats (+32% and +41%, respectively; P < .05), and were not different from sham values. CONCLUSIONS: Ischemic preconditioning counteracted ischemia-induced impairments of mitochondrial complexes I and II. These data support that ischemic preconditioning might be an interesting approach to reduce muscular injuries in the setting of ischemic vascular diseases.

Current outcome of elective open repair for infrarenal abdominal aortic aneurysm.

The outcome of conventional elective open repair for infrarenal abdominal aortic aneurysm (AAA) has improved mainly as a result of screening to detect coronary artery disease, the main risk factor for morbidity and mortality. Our group's policy is to perform routine coronary angiography in patients scheduled to undergo elective AAA repair. The purpose of this study was to evaluate morbidity and mortality in our department using this work-up strategy. From January 1990 to December 2000 we performed elective open repair on 632 patients, including 580 men (92%) and 52 women (8%). Preoperative coronary angiography performed in 607 cases (96%) revealed significant coronary disease in 53% of patients and led to the decision to propose prior myocardial revascularization in 12.5% of cases. Mortality and morbidity in the first 30 days after AAA repair were 1.4% and 15%, respectively. Analysis with the Cox model showed that the only risk factor for mortality was chronic renal insufficiency. Our data support routine use of coronary angiography prior to AAA repair. Screening and, if necessary, treatment of coronary artery disease that is commonly associated with AAA enhances the outcome of open AAA repair.

Modalities of preoperative imaging of the internal carotid artery used in France.

A survey of the 382 members of the Société de Chirurgie Vasculaire de Langue Française was conducted to determine preferred imaging techniques for preoperative assessment of the proximal internal carotid artery. A total of 180 questionnaires were returned concerning 9390 carotid stenoses treated in the year 2000. Doppler ultrasound (DUS), angiography, magnetic resonance angiography (MRA), and computed tomography angiography (CTA) were routinely used in 99%, 51.5%, 4%, and 3% of cases. Usual work-up methods involved DUS and angiography in 64% of cases, DUS and MRA in 7%, and DUS and CTA in 4% of cases. Indications for endarterectomy were based on DUS and angiography findings in 69% of cases, on DUS and MRA findings in 14%, on DUS and CTA findings in 9%, and on DUS findings alone in 8%. In-house access to CTA or MRA was more frequent at state-run institutions (p = 0.00001). Indication of endarterectomy based on DUS and MRA was more common at institutions equipped with technical facilities for MRA (21% vs. 8%; p = 0.001). An inverse correlation was observed between the number of carotid artery procedures performed and use of DUS and angiography work-up. The number of carotid endarterectomies without angiography is increasing in France. Preoperative DUS is still routinely used. Combined DUS and MRA is the preferred work-up for endarterectomy without angiography. Lack of access to MRA is still a limiting factor. Further study will be needed to evaluate the benefits and risks of endarterectomy without angiography.